Of these known supports, the invention relates more specifically to a pneumatically controlled, active hydraulic anti-vibration support designed to be inserted between two rigid elements and comprising:
first and second rigid frames designed to be joined respectively to the two rigid elements to be connected, PA1 an elastomer body linking the two frames to one another and partially delimiting a working chamber filled with liquid, PA1 a flexible wall, partially delimiting a compensation chamber filled with liquid, which is in turn connected to the working chamber by a throttled passage, also filled with liquid, PA1 a rigid partition which is joined to the second frame and which partially delimits the working chamber, this rigid partition having a mouthpiece closed off by means of a flexible membrane, said membrane having a first face communicating with the working chamber and a second face isolated from said working chamber, PA1 a pneumatic chamber partially delimited by the second face of the membrane, PA1 and at least one solenoid to provide communication between the pneumatic chamber and the atmosphere and/or with a coupling providing a connection to a pneumatic source, said solenoid being connected to an electrical connector in turn designed to be connected to an electronic control system. PA1 a rigid support block joined to the second frame, PA1 the solenoid, PA1 the pneumatic coupling, PA1 and the electrical connector, PA1 the sealed contact between the flexible membrane and the partition of the working chamber, PA1 and/or the sealed closure of the pneumatic chamber. PA1 the elastomer body is of a bell shape extending between a top integral with the first frame on the one hand and an annular base integral with the second frame on the other, the pneumatic actuating unit being contained in a rigid casing which is arranged opposing the elastomer body relative to the rigid partition, this casing being permanently joined to the second frame and to said rigid partition by applying the base of the elastomer body to the rigid partition, whilst the support block of the pneumatic actuating unit is retained between the casing and the rigid partition so that the annular flange of said support block is applied against the flexible membrane and the rigid partition; PA1 the compensating chamber is also arranged inside the casing; PA1 the membrane consists of a central part belonging to the flexible wall of the compensating chamber, said compensating chamber being annular in shape and being disposed around the pneumatic actuating unit; PA1 the flexible wall of the compensating chamber has a peripheral, metal reinforcing frame which is crimped onto the rigid partition and onto the second frame, pressing said second frame and the base of the elastomer body against the rigid partition; PA1 the casing is metal and is crimped on top of the peripheral reinforcing frame of the flexible wall; PA1 the flexible wall of the compensating chamber has, around its central part forming the flexible membrane, a rigid central frame which is embedded in said flexible wall and which has: PA1 the second frame forms a hollow crown which is open towards the rigid partition, delimiting the throttled passage in conjunction with said rigid partition; PA1 the support block of the pneumatic actuating unit also has a buffer reservoir inserted between the pneumatic coupling and the pneumatic chamber; PA1 the dimensions of the mouthpiece are such as to produce a natural resonance frequency of between 20 and 80 Hz; PA1 the single-block pneumatic actuating unit has an air passage which connects the solenoid to the pneumatic chamber and which is so dimensioned as to have a natural resonance frequency ranging between 20 and 80 Hz.
An anti-vibration support of this type is fitted in particular on the HARRIER vehicle sold by TOYOTA. In this known support, counter-vibrations are emitted in the working chamber at the idling frequencies of the engine by activating the solenoid so as to connect the pneumatic chamber alternately with the atmosphere and with the pneumatic source (in practice, a vacuum source formed by the air admission circuit of the engine).
This known anti-vibration support has the disadvantage of being relatively complex and expensive.